Search Results (14)

This study investigates the effect of a brand-new tank-mix adjuvant, Spray Adjuvant—Paraffinic Hydrocarbon Surfactant Complex (SA-PHSC), in enhancing the efficacy of commonly used insecticides and acaricides against two significant pests of tea plantations, the black looper (Hyposidra talaca) and the red spider mite (Oligonychus coffeae). Given the pest’s major influence on tea cultivation, which can result in output reductions of up to 55%, this study addresses mounting concerns of pesticide resistance and climate change. Laboratory bioassays showed that the combination of SA-PHSC with the insecticides quinalphos, deltamethrin, and emamectin benzoate, and acaricides etoxazole and fenpyroximate, significantly increased the mortality rates of H. talaca larvae (76.67–100.0%) and O. coffeae adults (100.0%). Additionally, enhancements were noted in the mechanisms of pest cuticular penetration and contact toxicity. These observations were corroborated by field trials, which demonstrated enhanced control of H. talaca (70.47–97.63%) and O. coffeae (75.87–96.59% reduction) populations, as well as increased green tea leaf yields, as a result of SA-PHSC treatment in conjunction with the evaluated pesticides. In addition, the study evaluated the phytotoxicity and organoleptic attributes of the made tea after application, confirming the safety and absence of any off-flavors in the final product (scoring 6.6–7.0). These findings indicate that SA-PHSC could serve as a valuable adjuvant for sustainable pest management in tea cultivation, as it has the ability to optimize the application of currently recommended insecticides and acaricides and restore pest susceptibility. Full article

A sensitive and reliable analytical method based on ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) was developed and validated for the simultaneous determination of bifenazate, cyflumetofen, etoxazole, and abamectin B_1a in citrus leaves, whole fruit, peel, and pulp. The method exhibited good linearity (0.0001–0.1 mg/L, R² > 0.999), a limit of quantification (LOQ) of 0.001 mg/kg, mean recoveries of 77.3–110.5%, and relative standard deviations of 3.1–19.8%. This method was applied to compare the dissipation dynamics and dietary risks of the four acaricides following knapsack spraying versus unmanned aerial vehicle (UAV) spraying. Compared to knapsack application, UAV spraying resulted in 2.2- to 4.1-fold higher initial deposits on citrus leaves and shorter dissipation half-lives. After 21 days, all terminal residues were below the maximum residue limits (MRLs) established by China, the Codex Alimentarius Commission, the United States, Australia, Korea, the European Union, and Japan. Chronic dietary risk assessment revealed risk quotients below 1% for cyflumetofen and etoxazole, and approximately 47% for bifenazate and 93% for abamectin B_1a. Although all values were below the acceptable threshold of 100%, the risk for abamectin B_1a approached this limit, indicating that its cumulative dietary risk should not be overlooked. This study provides scientific evidence for residue monitoring of acaricides in citrus and for the safety evaluation of UAV-based pesticide application. Full article

Intestinal health is critical for nutrient absorption and disease resistance in cultured fish. Yet, the effects of dietary Eucalyptus-derived biochar on the gut of largemouth bass (Micropterus salmoides) remain largely unexplored. This study evaluated whether supplementing diets with Eucalyptus biochar c profiles. In a 56-day feeding trial, M. salmoides were offered a standard diet containing either 0% (control) or graded levels of biochar. Juvenile fish (initial body weight 13.34 g) were randomly distributed into six groups with three replicates each (30 fish per replicate). Six extruded diets were formulated with 0, 2.5, 5.0, 10.0, 20.0, or 40.0 g kg⁻¹ of biochar, designated G0 through G5. Biochar had no significant effects on villus length, muscle layer thickness, villus width, or the activities of trypsin, amylase, and lipase, though goblet cell number was significantly higher in G5. mRNA expression of Claudin-3 and IL-10 was significantly upregulated in G1–G4, while IL-1β was significantly downregulated in G4 and G5, and TNF-α expression was reduced in G2 and G3. 16S rDNA sequencing showed increasing trends in the relative abundance of Firmicutes (43% to 49.17%) and Lactococcus (0% to 1.10%) in G3, accompanied by decreases in Proteobacteria and Klebsiella. Metabolomic analysis indicated significant upregulation of taurochenodeoxycholic acid-7-sulfate, apigenin, genistein, baicalein, taurocholic acid-3-sulfate, taurochenodeoxycholic acid-3-sulfate, and arginylmethionine in G3, whereas etoxazole and soyasaponin were significantly reduced. Dietary inclusion of 10 g kg⁻¹ Eucalyptus biochar improved intestinal health in largemouth bass by shaping the gut microbiota, promoting isoflavone biosynthesis and bile acid and amino acid metabolism, inhibiting the NF-κB pathway, and reinforcing the intestinal barrier. Full article

As a highly effective acaricide, etoxazole is widely used in agricultural production, but its toxicological effects on soil organisms remain unclear. Based on nuclear magnetic resonance (NMR) metabolomics technology, in this study, we systematically investigated the sublethal responses of earthworms (Eisenia fetida) to etoxazole. The results showed that etoxazole exposure significantly altered the endogenous metabolic profiles in earthworms, with 19 and 20 metabolites significantly changed after 2 and 14 d of exposure, respectively. Trimethylamine N-oxide exhibited specific changes, indicating that it may be a potential biomarker for exposure to etoxazole. KEGG pathway analysis revealed that five metabolic pathways were notably affected after 2 and 14 days of etoxazole exposure. These pathways were primarily associated with energy conversion, protein and amino acid synthesis and metabolism, carbohydrate metabolism, and nucleic acid and DNA synthesis. Overall, etoxazole exposure notably altered the endogenous metabolic profiles of earthworms. This study was of great significance for comprehensively understanding the potential hazards that etoxazole poses to soil ecosystems and provides important information for environmental monitoring and ecological risk assessment. Full article

In mountainous citrus orchards, the application of conventional ground sprayers for the control of citrus red mite (Panonychus citri) is often constrained by complex terrain and low operational efficiency. The Unmanned Aerial Spraying System (UASS), due to its low-altitude, low-volume, and high-maneuverability characteristics, has emerged as a promising alternative for pest management in such challenging environments. To evaluate the spray performance and field efficacy of different UASS types in controlling P. citri, five representative UASS models (JX25, DP, T1000, E-A2021, and T20), four mainstream pesticide formulations, and four novel tank-mix adjuvants were systematically assessed in a field experiment conducted in a typical hilly citrus orchard. The results showed that T20 delivered the best overall spray deposition, with upper canopy coverage reaching 10.63%, a deposition of 3.01 μg/cm², and the highest pesticide utilization (43.2%). E-A2021, equipped with a centrifugal nozzle, produced the finest droplets and highest droplet density (120.3–151.4 deposits/cm²), but its deposition and coverage were lowest due to drift. Nonetheless, it exhibited superior penetration (dIPR 72.3%, dDPR 73.5%), facilitating internal canopy coverage. T1000, operating at higher flight parameters, had the weakest deposition. Formulation type had a limited impact, with microemulsions (MEs) outperforming emulsifiable concentrates (ECs) and suspension concentrates (SCs). All adjuvants improved spray metrics, especially Yimanchu and Silwet, which enhanced pesticide utilization to 46.8% and 46.4% for E-A2021 and DP, respectively. Adjuvant use increased utilization by 4.6–11.9%, but also raised ground losses by 1.5–4.2%, except for Yimanchu, which reduced ground loss by 2.3%. In terms of control effect, the rapid efficacy (1–7 days after application, DAA) of UASS spraying was slightly lower than that of ground sprayers—electric spray gun (ESG), while its residual efficacy (14–25 DAA) was slightly higher. The addition of adjuvants improved both rapid and residual efficacy, making it comparable to or even better than ESG. E-A2021 with 5% abamectin·etoxazole ME (5A·E) and Yimanchu achieved 97.4% efficacy at 25 DAA. Among UASSs, T20 showed the rapid control, while E-A2021 outperformed JX25 and T1000 due to finer droplets effectively targeting P. citri. In residual control (14–25 DAA), JX25 with 45% bifenazate·etoxazole SC (45B·E) was most effective, followed by T20. 5A·E and 45B·E showed better residual efficacy than abamectin-based formulations, which declined more rapidly. Adjuvants significantly extended control duration, with Yimanchu performing best. This study demonstrates that with optimized spraying parameters, nozzle types, and adjuvants, UASSs can match or surpass ground spraying in P. citri control in hilly citrus orchards, providing valuable guidance for precision pesticide application in complex terrain. Full article

The two-spotted spider mite (Tetranychus urticae) is a highly destructive and economically significant pest in agricultural, horticultural, and ornamental agroecosystems worldwide, including hop (Humulus lupulus) and mint (Mentha spp.) fields in the Pacific Northwest (PNW) region of the United States. Repeated acaricide applications and rotations have led to widespread resistance, resulting in control failures. In this study, we investigated the mechanisms of resistance to four different acaricides (bifenthrin, bifenazate, etoxazole, and abamectin) across 23 field-collected TSSM populations by integrating diagnostic bioassays, genetic screening for resistance-associated mutations, structural modeling, and molecular docking. Several kdr mutations and mutation combinations were detected in TuVGSC across all tested populations. The G132A in Tucytb was identified in 68.75% of hop and 40% of mint TSSM populations, while the I1017F in TuCHS 1 was found in 94% of hop and 100% of mint populations. Structural analysis revealed key interactions between acaricides and target proteins in both wild-type and mutant variants, providing novel insights into the functional impacts of these mutations. Our findings enhance the understanding of TSSM adaptation to acaricides among different crops, supporting the development of more effective resistance management strategies to mitigate economic losses in hops, mint, and other crop production. Full article

The two-spotted spider mite (Tetranychus urticae) is a constant threat to greenhouse strawberry production. The application of synthetic acaricides is the main method of controlling T. urticae. However, resistance development to traditional acaricides reduces their efficacy and eventually leads to control failure. It is important for strawberry growers to look for new acaricides and application technologies that can limit the harmfulness of T. urticae in environmentally friendly ways. In the current study, laboratory toxicity tests and field trials were performed to screen high-efficiency acaricides, and then application technologies were improved to enhance the management of T. urticae. In the laboratory toxicity tests, the results showed that the LC₅₀ (median lethal concentration) value of cyetpyrafen, cyenopyrafen, cyflumetofen, bifenazate, abamectin, azocyclotin, pyridaben, spirodiclofen, and etoxazole against adult T. urticae was 0.226, 0.240, 0.415, 3.583, 5.531, 25.58, 39.69, 140.3, and 267.7 mg/L, respectively. In addition, the LC₅₀ value of the nine acaricides against eggs of T. urticae was 0.082, 0.097, 0.931, 18.56, 25.52, 45.61, 36.32, 1.954, and 0.040 mg/L, respectively. The field trial results showed that the best control effect was obtained in cyetpyrafen at 300 mL/ha treatment. Cyetpyrafen was chosen for further application technology tests. In the spray volume tests, the results showed that increasing the spray volume from 900 to 1050 L/ha significantly improved the control of T. urticae. In addition, the results from the spray instrument tests demonstrated that the control effects on T. urticae in the ozone spray treatments were significantly higher than those of the conventional and electrostatic sprays 1 and 3 days after treatment (DAT). Therefore, this study suggested that cyetpyrafen effectively controlled T. urticae both in the laboratory tests and in the field trials. Increasing the spray volume and application of ozone spray significantly improved T. urticae management. Full article

Nonthermal air plasma, which can be generated by air discharge, contains large amounts of reactive oxygen species (ROS), reactive nitrogen species (RNS) and high-energy particles. The ROS and RNS have strong oxidizing properties, and the high-energy particles can break chemical bonds in organic compounds, a process which can be used to degrade organic matter such as pesticides. In the present study, the effects of nonthermal air plasma on the degradation of several pesticides were investigated. An air plasma processing system was designed and constructed to produce nonthermal air plasma and to degrade five commonly used acaricides, namely, avermectin, bifenazate, spirodiclofen, etoxazole, and lufenuron, during the production of kumquat cuimi. The experimental results showed that nonthermal air plasma could degrade all the acaricides on the surface of the kumquat cuimi effectively. After 20 min of plasma treatment, the residues of avermectin, bifenazate, spirodiclofen, etoxazole and lufenuron on the surface of the kumquat cuimi were reduced by 80.67%, 79.52%, 62.40%, 48.93% and 23.11%, respectively. Further analysis indicated that the primary chemical bonds, hydrophobicity, and the pH value of the plasma-activated water can all affect the efficiency of pesticide degradation. Full article

Panonychus ulmi (Koch) (Acari: Tetranychidae), commonly known as European red mite, is a polyphagous pest of various tree and small fruit crops, including apples. A field study was conducted to evaluate different pesticide options available for the management of P. ulmi, and their impact on the population of non-target predatory mite species complex consisting of Neoseiulus fallacis, Typhlodromus pyri, and Zetzellia mali in apple orchards. Pesticides were applied using a commercial airblast sprayer at the 3–5 mite/leaf recommended economic Integrated Pest Management (IPM) threshold or prophylactically in the spring ignoring IPM practices such as monitoring, reliance on biological control and economic thresholds. Effects on the motile and egg stages of P. ulmi were evaluated as were effects on the populations of predatory mites through frequent leaf counts during the season. We also recorded the subsequent overwintering eggs of P. ulmi from each pesticide treatment. The two prophylactic treatments containing a mixture of zeta-cypermethrin + avermectin B1 + 1% horticultural oil and abamectin + 1% horticultural oil provided effective control of P. ulmi population throughout the season without reducing predatory mite populations. In contrast, eight treatments applied at the recommended economic threshold of 3–5 mites/leaf were not effective in suppressing P. ulmi populations and most reduced predatory mites. Etoxazole had significantly higher number of overwintering P. ulmi eggs compared to all other treatments. Full article

The objective of our study was to compare the effects of electron beam irradiation on the development and reproduction of Tetranychus urticae strains that were susceptible or resistant to acequinocyl, bifenazate, and etoxazole. Electron beam irradiation (50–400 Gy) was applied to T. urticae eggs, nymphs, and adults, after which the hatching rate, the emergence rate, longevity, and fecundity were analyzed. Eggs of all the T. urticae strains were irradiated with 150 Gy, and none of them hatched. When protonymphs were irradiated with 300 Gy, oviposition and thus F₁ hatchability in newly emerged adults were completely suppressed. The F₁ hatching rate of irradiated adults began to markedly decrease with a dose of 200 Gy, and all strains experienced 100% inhibition at a dose of 400 Gy. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (Sodium dodecyl sulfate polyacrylamide gel electrophoresis) showed substantial reductions in the levels of a 50 kDa protein in the susceptible and three resistant strains of T. urticae after irradiation with 400 Gy. These results indicate that a dose of 400 Gy was required to inhibit the normal development and reproduction of T. urticae, and susceptible and acaricide-resistant strains of T. urticae had identical radiosensitivities. Full article

The two-spotted spider mite Tetranychus urticae Koch is a major agricultural pest worldwide and is known to rapidly develop resistance to pesticides. In the present study, we explored a field strain that was collected in 2000 and 2003 and has been exhibiting resistance to etoxazole and pyridaben over the last 16 years. The resistance ratios of the etoxazole- and pyridaben-resistant strains (ER and PR) to etoxazole or pyridaben were more than 5,000,000- and 4109.6-fold higher than that of the susceptible strain, respectively. All field-collected populations showed resistance to etoxazole and pyridaben. The ER and PR strains showed cross-resistance to several acaricides. Both I1017F and H92R point mutations were detected in 7 out of 8 field groups. Spirodiclofen and spiromesifen resulted in more than 77.5% mortality in the 8 field groups. In addition, the genotype frequency of the I1017F point mutation was 100.0% in the ER strain, and that of the H92R point mutation was 97.0% in the PR strain. All of the field populations were found to have a high frequency of I1017F. These results suggest that the observation of resistance patterns will help in designing a sustainable IPM program for T. urticae. Full article

Field experiments were conducted in two commercial almond orchards located in the southern San Joaquin Valley during 2016 and 2017 to evaluate a “preventative” strategy to manage spider mites. Pacific mite, Tetranychus pacificus McGregor, was identified as the only mite species infesting the experimental sites in both years. We monitored mites weekly in 3.6-hectare plots over approximately 21 weeks in 2016 and in 2017 using guidelines developed by the University of California. In late May, prior to the detection of mites, preventative acaricide treatments, abamectin, cyflumetofen, or etoxazole were applied to the experimental plots at a field rate. In 2016 and 2017, mite densities in all the treatments increased at early-July, peaked at mid-August, and were undetectable by late August. Preventative acaricide-treated plots in 2016 tended to have significantly lower mite densities than in the untreated control plots. Although in 2017, densities in the acaricide-treated plots tended to not significantly differ from control plots. Mite feeding injury, measured as mean cumulative mite-days, did not exceed the economic threshold during the experiment. The biological control agent, sixspotted thrips, Scolothrips sexmaculatus (Pergande) likely played a role in controlling mite populations at mid and late August. Our results indicate that a preventative strategy does not play a definitive role in T. pacificus management on almond. Additionally, acaricides with the active ingredient, abamectin, are heavily relied on as preventative treatments. We assessed populations of T. pacificus from the mid and southern San Joaquin Valley and found increased tolerance to a medium level of resistance to the acaricide. Full article

The chiral separation of etoxazole enantiomers on Lux Cellulose-1, Lux Cellulose-3, Chiralpak IC, and Chiralpak AD chiral columns was carefully investigated by normal-phase high performance liquid chromatography and reverse-phase high performance liquid chromatography (HPLC). Hexane/isopropanol, hexane/n-butanol, methanol/water, and acetonitrile/water were used as mobile phase at a flow rate of 0.8 mL/min. The effects of chiral stationary phase, mobile phase component, mobile phase ratio, and temperature on etoxazole separation were also studied. Etoxazole enantiomers were baseline separated on Lux Cellulose-1, Chiralpak IC, and Chiralpak AD chiral columns, and partially separated on Lux Cellulose-3 chiral column under normal-phase HPLC. However, the complete separation on Lux Cellulose-1, Chiralpak IC, and partial separation on Chiralpak AD were obtained under reverse-phase HPLC. Normal-phase HPLC presented better resolution for etoxazole enantiomers than reverse-phase HPLC. Thermodynamic parameters, including ΔH and ΔS, were also calculated based on column temperature changes from 10 °C to 40 °C, and the maximum resolutions (R_s) were not always acquired at the lowest temperature. Furthermore, the optimized method was successfully applied to determine etoxazole enantiomers in cucumber, cabbage, tomato, and soil. The results of chiral separation efficiency of etoxazole enantiomers under normal-phase and reverse-phase HPLC were compared, and contribute to the comprehensive environmental risk assessment of etoxazole at the enantiomer level. Full article

We have evaluated the efficiency of silk fibroin (SF) coated with ZnO nanoparticles in the photocatalytic disappearance of one acaricide (etoxazole) and three fungicides (difenoconazole, myclobutanil and penconazole) in water exposed to sunlight irradiation. Electrospun SF/ZnO mats were successfully synthesized by electrospinning technique and characterized by XRD, FE-SEM, XPS, XDS, FTIR, and BET. The influence of catalyst loading on the degradation kinetics of the different pesticides was examined in order to gain knowledge of maximum degradation efficiency. A significant increment in degradation rates was observed with the addition of ZnO. SF mats with 25 mg of ZnO were finally selected since no significant differences (p < 0.05) were detected when the loading was enlarged from 25 to 50 mg for the majority of the compounds. In the experimental conditions, the half-lives ranged from 33 min to 93 min for etoxazole and myclobutanil, respectively. The comparison of SF materials coated with similar amount of TiO₂ and ZnO showed that the later was slightly more efficient to remove pesticide residues. Hence, the use of electrospun SF/ZnO nanostructures would provide an environmentally friendly approach with photocatalytic activity to be applied in the reclamation of water polluted by pesticides. Full article